煤矸石-磷石膏-菌渣混合基质与黑麦草根系复合体抗剪性能的差异性

Differential Shear Resistance of a Mixed Substrate of Gangue-Phosphogypsum-Mushroom Residue and Ryegrass Rhizosphere Complex

[目的]探究黑麦草生长对混合基质物理性质与抗剪性能的影响,为煤矸石山植被快速恢复和防治水土流失提供科学依据。[方法]针对煤矸石物理结构差和养分含量少等特点,通过在煤矸石中添加磷石膏和菌渣形成混合植生基质,在盆栽条件下种植黑麦草,探讨黑麦草生长对混合基质物理性质与抗剪性能的影响。[结果]①添加不同比例的磷石膏、菌渣改良煤矸石均可以明显促进黑麦草生长,其中在添加20%磷石膏和10%菌渣的煤矸石混合基质上黑麦草株高、地上部干生物量、根重密度和叶绿素含量指标改善效果最好,其次是添加10%磷石膏和10%菌渣的煤矸石。②添加磷石膏和菌渣可明显改善煤矸石混合基质的通气持水能力,其中添加20%磷石膏和10%菌渣处理组相对于只添加10%菌渣处理组煤矸石混合基质的自然含水率、总孔隙度、毛管孔隙度、非毛管孔隙度分别提高了18.88%,14.18%,13.12%和18.08%,而容重降低了24.76%。③添加磷石膏和菌渣的煤矸石混合基质有利于黑麦草根系的发育生长,相对于只添加10%菌渣处理组,添加20%磷石膏和10%菌渣处理组的煤矸石混合基质各级垂直荷载下的抗剪强度平均提高了71.71%,黏聚力和内摩擦角分别提高了102.84%,45.05%。[结论]添加20%磷石膏和10%菌渣的煤矸石混合基质与黑麦草根系复合体抗剪性能最好,有利于控制煤矸石山水土流失。

[Objective]The effects of ryegrass growth on the physical properties and shear resistance of a mixed substrate were studied in order to provide a scientific basis for the rapid restoration of coal gangue hill vegetation and for the prevention of soil erosion.[Methods]The physical structure of gangue is poor and the nutrient content is low.Ryegrass was planted in pots to which phosphogypsum and mycorrhizal residue were added to determine the effect of ryegrass growth on the physical properties and shear resistance of a mixed substrate.[Results]①The addition of different proportions of phosphogypsum and mycorrhizal slag significantly increased the growth of ryegrass.Height,aboveground dry biomass,root weight density,and chlorophyll content of ryegrass on the mixed coal gangue substrate consisting of 20%phosphogypsum and 10%mycorrhizal slag had the best effect,followed by the mixed substrate consisting of 10%phosphogypsum and 10%mycorrhizal slag.②The addition of phosphogypsum and slag significantly increased the aeration and water-holding capacity of the gangue mixed substrate in which the natural water content,total porosity,capillary porosity,and non-capillary porosity of the gangue mixed substrate with 20%phosphogypsum and 10%slag were increased by 18.88%,14.18%,13.12%,and 18.08%,respectively,and the bulk density was decreased by 24.76%compared with the respective values observed for the gangue mixed substrate with only 10%slag.③The shear strength of the gangue mixed substrate with 20%phosphogypsum and 10%mycorrhizal slag increased by 71.71%,and the cohesion and internal friction angle increased by 102.84%and 45.05%,respectively,compared with the mixed substrate having only 10%mycorrhizal slag.[Conclusion]The coal gangue mixed substrate with ryegrass root complex having 20%phosphogypsum and 10%mycorrhizal residue had the greatest shear resistance and was beneficial for controlling soil erosion in coal gangue hills.